JP4289269B2 - Optical display device, optical display device control program, and optical display device control method - Google Patents

Description

  The present invention relates to an apparatus, a program, and a method for controlling the gradation of an image by controlling the transmission state of light from a light source through a plurality of optical transmission elements optically arranged in series. The present invention relates to an optical display device, an optical display device control program, and an optical display device control method suitable for realizing a luminance dynamic range and an increase in the number of gradations.

In recent years, LCD (Liquid Crystal Display), EL, plasma display, CRT (Cathode Ray Tube), projectors, and other optical display devices have seen remarkable improvements in image quality, and the resolution and color gamut have achieved performance that is almost comparable to human visual characteristics. It is being done. However, regarding the luminance dynamic range, the reproduction range is limited to about 1 to 10 ² [nit], and the number of gradations is generally 8 bits. On the other hand, human visual perception has a luminance dynamic range perceived at a time of about 10 ⁻² to 10 ⁴ [nit], and the luminance discrimination capability is about 0.2 [nit], which is the number of gradations. Is converted to 12 bits. Looking at the display image of the current optical display device through such visual characteristics, the narrowness of the luminance dynamic range is conspicuous, and in addition, the reality and power of the display image are insufficient due to the lack of gradation in the shadow part and highlight part. Will feel unsatisfactory.

  Further, in computer graphics (hereinafter abbreviated as CG) used in movies, games, etc., display data (hereinafter referred to as HDR (High Dynamic Range) display data) that represents a luminance dynamic range and gradation number close to human vision. The movement of pursuing the reality of depiction is being mainstream. However, since the performance of the optical display device that displays it is insufficient, there is a problem that the expressive power inherent in the CG content cannot be fully exhibited.

Further, the next OS (Operating System) is scheduled to adopt a 16-bit color space, and the luminance dynamic range and the number of gradations are dramatically increased as compared with the current 8-bit color space. Therefore, it is desired to realize an optical display device that can make use of the 16-bit color space.
Among optical display devices, projection display devices such as liquid crystal projectors and DLP (Digital Light Processing, trademark of TI) projectors are capable of displaying large screens and are effective in reproducing the reality and power of displayed images. Device. In this field, the following proposals have been made to solve the above problems.

  As a projection display device with a high dynamic range, for example, there is a technique disclosed in Patent Document 1, which includes a light source, a first light modulation element that modulates luminance in the entire wavelength region of light, and a wavelength region of light. Among these, each wavelength region of the RGB three primary colors is provided with a second light modulation element that modulates the luminance of the wavelength region, and the light from the light source is modulated by the first light modulation element to form a desired luminance distribution, and its optical image Is imaged on the pixel surface of the second light modulation element, color-modulated, and second-order modulated light is projected. Each pixel of the first light modulation element and the second light modulation element is individually controlled based on the first control value and the second control value determined from the HDR display data. As the light modulation element, a transmission type modulation element having a pixel structure or a segment structure whose transmittance can be controlled independently and capable of controlling a two-dimensional transmittance distribution is used. A typical example is a liquid crystal light valve. A reflective modulation element may be used instead of the transmission modulation element, and a representative example thereof is a DMD (Digital Micromirror Device) element.

  Consider a case where a light modulation element having a dark display transmittance of 0.2% and a bright display transmittance of 60% is used. With a single light modulation element, the luminance dynamic range is 60 / 0.2 = 300. Since the conventional projection display apparatus corresponds to optically arranging light modulation elements having a luminance dynamic range of 300 in series, a luminance dynamic range of 300 × 300 = 90000 can be realized. The same idea holds for the number of gradations, and an 8-bit gradation light modulation element is optically arranged in series, whereby a gradation number exceeding 8 bits can be obtained.

However, when a DMD is used as a light modulation element, the DMD cannot change the light transmittance or reflectance in terms of physical properties. Therefore, the light reflection direction (two directions) in the micromirrors constituting the DMD and its It is necessary to devise such as changing the apparent reflectance by controlling the duration with the pulse width of the control signal (PWM control). As described above, as a method for realizing gradation display of an image by controlling two states of transmission and non-transmission of light in a specific direction, according to the number of gradations of each pixel of the image as in the field sequential method. A method is conceivable in which a plurality of control signals having different pulse widths are generated, and the accumulated transmission time of light to a target position is time-division controlled by these generated control signals.
Japanese Patent Laid-Open No. 2001-1000068

However, in the invention described in Patent Document 1, there is no specific method for realizing the expansion of the luminance dynamic range and the number of gradations when DMD is used as the first light modulation element and the second light modulation element. .
Further, as described above, when the first light modulation element and the second light modulation element are controlled by the field sequential method to realize the gradation display of the image, the first light modulation element and the second light modulation element are synchronized. If controlled, the gradation of the image can be displayed only with the number of gradations that can be realized with only one of the modulation elements. Therefore, the number of gradations cannot be increased by simple synchronous control.

  In addition, when a liquid crystal light valve is used as the first light modulation element and the second light modulation element, the aperture ratio becomes about 60% due to the fabrication of semiconductor components and the like. The transmittance is 60% and the light utilization efficiency is lowered. That is, when a transmissive liquid crystal light valve having an aperture ratio of 60% is used as the first light modulation element and the second light modulation element, the aperture ratio is 60 [%] × 60 [%] = 36 [%]. The transmittance is reduced to 36%.

  Therefore, the present invention was made paying attention to such an unsolved problem of the conventional technology, and controls the transmission state and non-transmission state of light in a specific direction in the light transmission element, An object is to provide an optical display device, an optical display device control program, and an optical display device control method that are suitable for realizing an increase in the luminance dynamic range and the number of gradations of a display image and improving light utilization efficiency. Yes.

[Invention 1 ] In order to achieve the above object, an optical display device according to Invention 1 includes an optical transmission element having a plurality of optical transmission units capable of independently controlling the transmission state and non-transmission state of incident light in a predetermined direction. Two or more optically arranged in series, and an apparatus for displaying an image by controlling the transmission state and non-transmission state of light from a light source via the two or more light transmission elements In order to control the transmission state and non-transmission state of the light transmission element, a plurality of control signals having specific pulse widths corresponding to specific bits in a bit string indicating the number of gradations are generated based on the number of gradations of the display image. A control signal supply means capable of supplying the generated control signal in a time-sharing manner and at a timing synchronized with each of the two or more optical transmission elements, and a delay time for the control signal having the specific pulse width based on the specific bit. Calculate Based on the calculated delay time of said two or more optical transmission element than the timing for supplying the control signal of the certain pulse width to one, supplies a control signal of the certain pulse width to another optical transmission device It is characterized by comprising signal delay means capable of delaying the timing to perform a predetermined time.

  With such a configuration, the control signal supply means generates a control signal for controlling the transmission state and the non-transmission state of the light transmission element based on the number of gradations of the display image, and the generated control signal is used as the control signal. It is possible to supply to each of the two or more light transmission elements at a synchronized timing, and the signal delay means supplies one of the two or more light transmission elements (hereinafter referred to as the first light transmission element) to the above-described one. It is possible to delay the timing of supplying the control signal to another light transmission element (hereinafter referred to as a second light transmission element) by a predetermined time from the timing of supplying the control signal.

  Therefore, by adjusting the delay time, the light can be transmitted to the target position only during the time when the light transmission time of the first light transmission element and the light transmission time of the second light transmission element partially overlap each other. It becomes possible. In other words, as described above, by using the time difference between the control signals supplied to two or more light transmission elements to more precisely control the light transmission time to the target position, the number of displayable gradations is two or more. The effect that the number of gradations that can be displayed can be expanded by the synchronous control of the light transmission element is obtained.

In addition, a relatively high luminance dynamic range can be realized by using a high luminance light source. The light source may be any medium that generates light. For example, the light source may be a light source built in an optical system such as a lamp, or may be a sun or indoor light. It may use light from the outside world.
Further, with such a configuration, the transmission time of light in a specific direction can be easily controlled by the pulse width, and the gradation display of the image based on the number of gradations of the display image can be performed more accurately. The effect that it can be obtained. In addition, it is possible to easily perform time-division control of gradation display of an image such as a field sequential method.
In addition, with such a configuration, it is possible to supply the control signal to two or more light transmission elements at a synchronized timing and in a time-sharing manner. Therefore, by adjusting the delay time for each control signal supplied in a time-sharing manner, the target position is set by the difference between the light transmission time of the first-stage light transmission element and the light transmission time of the second-stage light transmission element. It is possible to transmit light in a time division manner. As a result, it is possible to increase the number of displayable gradations.
With such a configuration, the control signal supply unit can generate a control signal having a specific pulse width corresponding to a specific bit in the bit string indicating the number of gradations, and the signal delay unit includes: A delay time for the control signal having the specific pulse width is calculated based on the specific bit, and the control signal having the specific pulse width is supplied to any one of the two or more optical transmission elements based on the calculated delay time. It is possible to delay the timing at which the control signal having the specific pulse width is supplied to the other light transmission elements, rather than the timing to perform the above.
For example, when the number of gradations of the display image exceeds a predetermined number of gradations, the control signal supply means sets a bit corresponding to the number of gradations exceeding that as a specific bit, and a specific pulse width corresponding thereto The control signal is generated and supplied to any one of the two or more optical transmission elements. On the other hand, the signal delay means sets a delay time for the control signal having a specific pulse width based on the specific bit. It is possible to delay the supply timing of the control signal having the specific pulse width to the other optical transmission elements based on the calculated delay time.
Therefore, the number of displayable gray levels can be reduced to two by controlling the transmission time of light to the target position more finely by using the time difference between the control signals having specific pulse widths supplied to two or more light transmission elements. The effect that the number of gradations that can be displayed can be expanded by the above-described synchronization control of the light transmission elements can be obtained.
In addition, a relatively high luminance dynamic range can be realized by using a high luminance light source.

[Invention 2] Further, in the optical display device of Invention 2, in the optical display device of Invention 1, the specific pulse width is a control signal corresponding to the least significant bit excluding the specific bit in the bit string indicating the number of gradations. It is characterized by the same pulse width.

With such a configuration, it is easy to calculate the delay time according to the number of gradations of the display image, and an effect is obtained that the delay supply control of the control signal can be easily performed.

[Invention 3] The optical display device of Invention 3 is characterized in that, in the optical display device of Invention 1 or 2, the supply interval of the control signal of the specific pulse width is made larger than the specific pulse width. .

With such a configuration, a control signal newly supplied to any one of the two or more light transmission elements and a previous signal that is delayed and supplied to the other light transmission elements Since the control signal can be prevented from overlapping, the effect of performing time-division control for stable gradation display can be obtained.

[Invention 4] The optical display device according to Invention 4 is the optical display device according to any one of Inventions 1 to 3, wherein the number of specific bits is n (n is an integer) and the number of gradations of the display image is indicated. When the bit position of the specific bit in the bit string is m (m is an integer of 0 to (n-1)), the signal delay means adds the specific pulse width to the coefficient obtained by (2n-2m) / 2n. The time obtained by multiplying the time is calculated as the delay time of the control signal having the specific pulse width.
With such a configuration, the delay time of the control signal having a specific pulse width can be easily calculated by the above formula, so that an effect of easily generating a circuit, a program or the like for obtaining the delay time can be obtained. It is done.

[Invention 5] The optical display device of Invention 5 is the optical display device of any one of Inventions 1 to 4, wherein the signal delay means is any one of the plurality of control signals based on the number of gradations. It is characterized in that one is delayed for a predetermined time.
With this configuration, the control signal supply means can generate a plurality of control signals based on the number of gradations of the display image, and the signal delay means can generate the control signal based on the number of gradations. Any one of the plurality of control signals can be delayed for a predetermined time.
Therefore, by adjusting the delay time for any one of the plurality of control signals, an effect that the number of displayable gradations can be increased can be obtained.

[Invention 6] The optical display device of Invention 6 is the optical display device of any one of Inventions 1 to 5, wherein the signal delay means is any one of the plurality of control signals based on the number of gradations. One generation timing is delayed by a predetermined time.
With this configuration, the control signal supply means can generate a plurality of control signals based on the number of gradations of the display image, and the signal delay means can generate the control signal based on the number of gradations. It is possible to delay the generation timing of any one of the plurality of control signals for a predetermined time.
Therefore, by adjusting the delay time for any one of the plurality of control signals, an effect that the number of displayable gradations can be increased can be obtained.

[Invention 7 ] Further, in the optical display device of Invention 7, in the optical display device of any one of Inventions 1 to 6 , the number of the light transmitting portions in the two or more light transmitting elements is set between the light transmitting elements. Is characterized by equality.
With such a configuration, the number of the light transmission units of the two or more light transmission units is configured to be equal to each other. Therefore, accurate gradation expression can be performed for each pixel of the display image, and the image height is increased. An effect that a contrast display can be realized is obtained.

[Invention 8 ] Further, the optical display device of Invention 8 is characterized in that, in the optical display device of any one of Inventions 1 to 7 , the two or more light transmission elements are reflection type light transmission elements. .
In such a configuration, if a reflective light transmission element such as a DMD or a reflective liquid crystal light valve is used as the two or more light transmission elements, light in a specific direction can be obtained in each light transmission element with almost no loss. Can be transmitted, and the light use efficiency can be improved.

[Invention 9 ] In order to achieve the above object, an optical display device control program according to Invention 9 comprises a plurality of light transmission units capable of independently controlling the transmission state and non-transmission state of incident light in a predetermined direction. An optical display comprising two or more optical elements arranged in series and displaying an image by controlling the transmission state and non-transmission state of light from a light source via the two or more light transmission elements A program for controlling an apparatus, wherein a specific pulse corresponding to a specific bit in a bit string indicating the number of gradations based on the number of gradations of the display image for controlling the transmission state and non-transmission state of the light transmission element A plurality of control signals having a width, control signal supply means capable of supplying the generated control signals in a time-sharing manner and in synchronization with the two or more optical transmission elements, and the specific pulse based on the specific bits. A delay time with respect to the control signal having a pulse width , and other than the timing of supplying the control signal having the specific pulse width to any one of the two or more light transmission elements based on the calculated delay time . It is a program for causing a computer to execute processing realized as signal delay means capable of delaying the timing for supplying the control signal having the specific pulse width to the optical transmission element for a predetermined time.

Here, the present invention is a program for controlling the optical display device according to the first aspect , and the description thereof is omitted because the effects overlap.

[Invention 10 ] In order to achieve the above object, an optical display device control method according to Invention 10 includes a plurality of light transmission units capable of independently controlling the transmission state and non-transmission state of incident light in a predetermined direction. An optical display comprising two or more optical elements arranged in series and displaying an image by controlling the transmission state and non-transmission state of light from a light source via the two or more light transmission elements A method for controlling an apparatus, comprising: a specific pulse corresponding to a specific bit in a bit string indicating the number of gradations based on the number of gradations of the display image in order to control the transmission state and non-transmission state of the light transmission element a control signal having a width a plurality generate a control signal supply step of supplying at a timing synchronized respectively and the two or more light transmitting elements in a time sharing control signal thus generated, the specific pulse width on the basis of the specific bit System A delay time with respect to the control signal is calculated , and other light transmission elements than the timing of supplying the control signal having the specific pulse width to any one of the two or more light transmission elements based on the calculated delay time. And a signal delay step capable of delaying a timing for supplying the control signal having the specific pulse width for a predetermined time.

Here, the present invention is a method realized by the optical display device or the like of the first aspect , and since the effect is duplicated, the description is omitted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 13 are diagrams showing an embodiment of a projection display device to which an optical display device, an optical display device control program, and an optical display device control method according to the present invention are applied.
First, the main optical configuration of the projection display device 1 according to the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a main optical configuration of a projection display device 1 according to the present invention.

As shown in FIG. 1, the projection display device 1 includes a light source 10, a color filter 30, a first DMD 50, a second DMD 70, and a projection lens 100, which are optically connected in series. It is the composition arranged in.
The light source 10 is composed of a light source lamp such as an ultra-high pressure mercury lamp or a xenon lamp, and a reflector that collects light from the light source.

The first DMD 50 and the second DMD 70 are arranged in a matrix of a plurality of micromirrors that can independently control the reflection angle of incident light (for example, two angles of 12 ° and −12 °) by an external control signal. It has an arrangement configuration.
The color filter 30 has a configuration in which a dichroic film corresponding to each of three color lights of red (R), green (G), and blue (B) is coated on the surface of a single circular glass. Furthermore, the self is rotated in accordance with a control signal from the outside, and the surface disposed on the optical path is switched to the surface of the dichroic film corresponding to one of the three colors. Then, only the corresponding color light of the white light incident from the light source is transmitted and emitted toward the first DMD 50.

The projection lens 100 is for projecting the light reflected by the second DMD 70 onto the screen 110 and displaying a desired image on the screen 110.
As shown in FIG. 1, the condenser lens 20 is provided on the incident side of the color filter 30, the condenser lens 40 is provided on the incident side of the first DMD 50, and the condenser lens is provided on the incident side of the second DMD 70. 60 are arranged respectively. These condensing lenses 20, 40, and 60 have a function of efficiently transmitting light to optical elements disposed in the subsequent stages. Here, a lens having a function of adjusting the distribution of the exit angles of incident light is used as the condenser lens.

  Explaining the overall light transmission flow of the projection display device 1, white light from the light source 10 enters the color filter 30 through the condenser lens 20, and RGB 3 in the dichroic film of the color filter 30. Only light of one of the primary colors is transmitted. The transmitted color light is incident on the first DMD 50 via the condenser lens 40. The first DMD 50 reflects incident color light in a direction according to the reflection angle of the micromirror.

In the present embodiment, the reflected light from the first DMD 50 is reflected toward the second DMD 70 at the subsequent stage at one reflection angle, and is reflected toward the light absorbing material (not shown) at the other reflection angle. In addition, the first DMD 50 and the optical elements at the front and rear stages thereof are arranged.
Further, the light reflected by the first DMD 50 toward the second DMD 70 is incident on the second DMD 70 via the condenser lens 60. This incident light is reflected in the direction according to the reflection angle of the micromirror in the second DMD 70, similarly to the first DMD 50.

In the present embodiment, the reflected light from the second DMD 70 is reflected toward the projection lens 100 at the subsequent stage at one reflection angle, and is reflected toward the light absorbing material (not shown) at the other reflection angle. In addition, the second DMD 70 and the optical elements at the front and rear stages thereof are arranged.
The light reflected by the second DMD 70 toward the projection lens 100 is projected onto the screen 110 via the projection lens 100. A desired image is displayed on the screen 110 by the projected light.

Further, the projection display device 1 includes a display control device 2 that controls the first DMD 50 and the second DMD 70. Hereinafter, based on FIG. 2, the structure of the display control apparatus 2 is demonstrated in detail.
FIG. 2 is a block diagram illustrating a hardware configuration of the display control device 2.
As shown in FIG. 2, the display control device 2 includes an interface circuit 2 a that acquires signals from the outside such as HDR video signals and RGB signals, and transmits various signals to each component, and the first DMD 50. A mirror device driving circuit 2b for driving and controlling the micromirror of the second DMD 70, a mirror device driving circuit 2c for driving and controlling the micromirror of the second DMD 70, and a CPU 2d for controlling the calculation and the entire system based on the control program; The ROM 2e stores a control program for the CPU 2d in a predetermined area in advance, and a RAM 2f for storing data read from the ROM 2e or the like and calculation results necessary for the calculation process of the CPU 2d. Further, the interface circuit 2a, the CPU 2d, the ROM 2e, and the RAM 2f are connected to each other via a bus 2g that is a signal line for transferring data so that data can be exchanged.

In the present embodiment, the projection display device 1 performs time-sharing control of the reflection angles of the micromirrors of the first and second DMDs 50 and 70 in the display control device 2 based on the HDR video signal and the RGB signal from the outside, An HDR image is displayed on the screen 110.
Here, the HDR image data is image data capable of realizing a high luminance dynamic range that cannot be realized by a conventional image format such as sRGB, and stores pixel values indicating pixel luminance levels for all pixels of the image. Yes. In the present embodiment, the HDR display data uses a format in which a pixel value indicating a luminance level for each of the three primary colors of RGB is stored as a floating point value for one pixel. For example, the value (1.2, 5.4, 2.3) is stored as the pixel value of one pixel.

  Also, the HDR image data is generated based on a HDR image having a high luminance dynamic range and a captured HDR image. For details of the method for generating HDR image data, for example, publicly known document 1 “PEDebevec, J. Malik,“ Recovering High Dynamic Range Radiance Maps from Photographs ”, Proceedings of ACM SIGGRAPH 97, pp. 367-378 (1997). It is published in.

  In the present embodiment, the projection display device 1 corresponds to a 16-bit representation format per pixel, and the HDR image data has a data format in which each pixel is represented by a 16-bit floating point. . Here, since it is necessary to give a control value of the same format to the DMD, it is necessary to convert it to a 16-bit control value in some cases. Further, in the case of an input signal of 16-bit floating point expression such as HDR image data, normalization is performed by image processing such as maximum luminance correction, and thereafter, conversion to a 16-bit control value is performed.

Further, specific HDR image display control processing in the display control device 2 will be described with reference to FIGS. 3 and 4.
FIG. 3 is a diagram illustrating a basic waveform used for display control, and FIG. 4 is a diagram illustrating an example of a drive control waveform for expanding the number of gradations of an HDR image.
First, the interface circuit 2a acquires an external HDR video signal and RGB signal, converts the acquired signals into digital data, and transmits the digital data to the RAM 2f. The RAM 2f stores the transmitted HDR video data and RGB data in a predetermined memory area.

  On the other hand, the CPU 2d starts a control program in response to power-on, operates when HDR image data is stored in a specific area of the RAM 2f, and analyzes the HDR video data and RGB data stored in the RAM 2f. Then, information on the number of gradations of each pixel is extracted, and waveform information of a control signal for driving each micromirror of the first DMD 50 and the second DMD 70 is generated based on the number of gradations. In the present embodiment, the number of gradations is expressed as a sum of numerical values that can be expressed by a multiplier of 2, and as shown in FIG. 3, a pulse width waveform corresponding to each numerical value is generated as a control signal. Here, FIG. 3 shows a driving waveform for one pixel (one micromirror) of the DMD. The reflection angle of the DMD micromirror is light in the target direction for a time of a pulse width corresponding to a multiplier of 2. Is controlled to reflect. For example, when the number of gradations is “133” in decimal, it is expressed in the form of the sum of “1 + 4 + 128” and a multiplier of 2, and pulses corresponding to the constituent elements “1”, “4”, and “128”, respectively. Generate a width control signal.

However, the description of the generation of the waveform information is for a case where attention is paid to one pixel of the HDR image, and it is actually necessary to generate the waveform information for all the pixels of the HDR image.
Here, in the present embodiment, the maximum number of gradations of an image that can be displayed when the first DMD 50 and the second DMD 70 are synchronously controlled is 8 bits. Further, by supplying a high-level control signal (waveform rising period) to each of the first DMD 50 and the second DMD 70, light from the light source 10 is directed toward the projection lens 100 for a time corresponding to the pulse width. Is reflected so that the reflection direction of each micromirror is controlled. That is, when a high-level signal is not supplied (waveform falling period), the reflection directions of the first and second DMDs 50 and 70 are controlled so as to reflect incident light toward the light absorbing material. .

  The waveform information of the control signal generated by the control program is transmitted to the mirror device drive circuits 2b and 2c via the interface circuit 2a. The mirror device drive circuits 2b and 2c generate control signals based on the acquired waveform information, and supply the control signals generated at the synchronized timing to the first DMD 50 and the second DMD 70 in a time division manner. Drive control of the reflection angle and reflection time of the micromirror is performed. That is, gradation is expressed by the accumulated transmission time of light by performing time division control and PWM (Pulse Width Modulation) control using a plurality of control signals having different pulse widths. Thus, the two states of light transmission and non-transmission to the projection lens 100 and the light transmission time are controlled according to the number of gradations, and the HDR image is displayed on the screen 110 in gradation.

Furthermore, in the present embodiment, it is possible to display an HDR image in which the number of gradations is enlarged and the number of gradations exceeds 8 bits.
For example, consider an HDR image with the number of gradations “1669”. In order to realize the gradation number “1669”, an ability to display an 11-bit gradation number is required. That is, it is necessary to further add control for performing gradation display for 3 bits corresponding to “1024”, “512”, and “256”.

  In order to realize the above 11-bit gradation display, in the present embodiment, the pulse width control corresponding to “128” among the control signals of the pulse width corresponding to the 8-bit gradation number at the time of synchronous control. The signal is made to correspond to “1024”, and similarly, the control signals respectively corresponding to “64 to 1” are made to correspond to “512 to 8”. Then, the remaining 3 bits corresponding to “4”, “2”, and “1” are handled as additional bits. For the additional 3 bits, three control signals having a pulse width corresponding to “1” in the synchronous control are used. That is, the control signal having the minimum pulse width at the time of synchronous control is used as an additional control signal.

  Further, the three control signals are supplied to the second DMD 70 after a predetermined time delay from the timing of supplying them to the first DMD 50. That is, by delaying the supply of the control signal to the second DMD 70, the light transmission time of the first DMD 50 and the light transmission time of the second DMD 70 are partly overlapped with each other at the target position. Transmit light. Therefore, by adjusting the respective delay times so that light is transmitted to the projection lens 100 only for the time corresponding to each bit of “4”, “2”, and “1”, the additional amount is obtained. The light transmission time corresponding to 3 bits can be controlled. However, the delay time needs to be different for each additional control signal and shorter than the pulse width of each control signal.

A specific operation of the gradation display processing of the HDR image by the above-described gradation number expansion will be described with reference to FIG. For convenience of explanation, FIG. 4 illustrates a case where the number of gradations that can be displayed at the time of synchronization control is 3 bits, and an HDR image having a gradation number of 6 bits is displayed as gradations.
First, an HDR video signal and an RGB signal corresponding to HDR image data having a 6-bit gradation number are input from the outside via the interface circuit 2a. The input signal is stored as digital data in a specific area of the RAM 2f, whereby the control program starts operating. Here, the operation will be described focusing on one pixel of the gradation number “47” in the HDR image.

  Based on the number of gradation levels (6 bits), the control program first calculates the number of additional bits “3”. Next, waveform information of the control signal for the upper 3 bits of the gradation number “47 (101111)” is generated. In this case, the waveform information of the control signal corresponding to the upper 3 bits “101” is generated. This waveform information corresponds to the pulse width control signal used in the synchronous control as described above. Therefore, the control signal having the pulse width corresponding to the bits “8” and “1” in the gradation number of 3 bits corresponds to 1 bit in the upper 3 bits.

Furthermore, the control program generates waveform information of the control signal corresponding to the lower 3 bits “111”. Here, the lower 3 bits are treated as additional bits, and correspond to the 3 bits at the time of synchronous control. Waveform information for adding three pulse width waveforms corresponding to “1” in the pulse width control signal is generated. Hereinafter, a control signal added as an additional bit is referred to as a specific control signal. When the additional number of specific control signals is determined, the delay time of each specific control signal is calculated. In the present embodiment, the delay time is calculated using the following equation (1). The delay time is calculated by multiplying the numerical value calculated in Equation (1) by the time of the pulse width of the specific control signal.

(2 ⁿ -2 ^m ) / 2 ⁿ (1)

However, the number of additional specific control signals is n, and the corresponding bit position of the additional bit in the gradation data is m.

In the case of the gradation number “47 (101111)”, the additional number n is 3, and the corresponding bit position m is “2, 1, 0 corresponding to the second bit, the first bit, and the 0th bit in the lower 3 bits, respectively. ”. When these numerical values are substituted into the above formula (1), “(2 ³ −2 ² ) / 2 ³ = 4/8”, “(2 ³ −2 ¹ ) / 2 ³ = 6/8”, “(2 ³ −2 ⁰ ) / 2 ³ = 7/8 ”is calculated.

By multiplying the calculation result by the time of the pulse width of the specific control signal, the delay time of the specific control signal corresponding to the corresponding bit position “2, 1, 0” is calculated.
Thus, when the number of additional bits and the delay time are calculated, the waveform information corresponding to the upper 3 bits and the information on the number of additional bits are transmitted to the mirror device drive circuit 2b via the interface circuit 2a, while the upper 3 Waveform information corresponding to bits, information on the number of additional bits, and delay time information are transmitted to the mirror device drive circuit 2c via the interface circuit 2a.

  The mirror device drive circuits 2b and 2c generate a control signal based on the acquired information, and the first DMD 50 and the second DMD 70 are synchronized with respect to the control signal corresponding to the upper 3 bits of the number of gradations of the HDR image. To each micromirror. On the other hand, the specific control signal corresponding to the lower 3 bits of the number of gradations of the HDR image is supplied to the first DMD 50 in order from the upper bits, and each of the above calculated values from the timing supplied to the first DMD 50. The signal is supplied to the second DMD 70 after being delayed by a delay time (the phase is controlled).

  That is, as shown by 40a in FIG. 4, the control signal supplied to one pixel (one micromirror) of the first DMD 50 is a control signal having a pulse width of a bit corresponding to “32” out of the upper 3 bits. In addition to the control signal of the pulse width of the bit corresponding to “8”, three specific control signals for the additional bits are supplied at the timing indicated by 40a. It should be noted that the numerical value indicated above the control signal in FIG. 4 indicates time, the time of the pulse width corresponding to “32” is “4”, and the time of the pulse width corresponding to “8” is “1”. “, The time of the pulse width corresponding to the specific control signal is“ 1 ”. Further, in FIG. 4, the numerical value written between the control signals also represents time, and in the control signal corresponding to the upper 3 bits, the time interval between the control signals is “1”, and the specific control signal The time interval between them is “2”. That is, the time interval between the specific control signals is a time interval that is twice the pulse width of the specific control signal. By setting the time interval twice, the specific control signal supplied to the second DMD 70 with a delay is prevented from overlapping with the specific control signal supplied to the first DMD 50 next.

  On the other hand, the control signal supplied to one pixel (one micromirror) of the second DMD 70 is the same as the control signal supplied to one pixel of the first DMD 50 as shown by 40b in FIG. As shown by 40c in FIG. 4, the control signal corresponding to the upper 3 bits is synchronized with the timing supplied to the first DMD 50, and the above-described calculated delay time is used for the three specific control signals corresponding to the lower 3 bits. Each specific control signal is delayed by (4/8, 6/8, 7/8). In addition, the numerical value described under the specific control signal shown in FIG. 4 is a corresponding bit position. That is, as indicated by 40c in FIG. 4, the specific control signal corresponding to the bit position “2” is delayed by “4/8”, and the specific control signal corresponding to the bit position “1” is only “6/8”. The specific control signal corresponding to the bit position “0” is delayed by “7/8” and supplied to the second DMD 70. Here, as indicated by 40c in FIG. 4, the supply timing of the specific control signal supplied to one pixel of the first DMD 50 is a dotted signal waveform.

  The mirror device driving circuits 2b and 2c supply a control signal to each pixel of the first and second DMDs 50 and 70 based on the waveform information at the timing indicated by 40c in FIG. As indicated by 40d in FIG. 4, light is transmitted in a time-sharing manner for the upper 3 bits for the time of the pulse width of the supplied control signal. On the other hand, for the lower 3 bits, light is transmitted in a time-sharing manner for a time partly overlapped by the deviation due to the delay time of the specific control signals respectively supplied to the first DMD 50 and the second DMD 70. Specifically, for the lower 3 bits, as shown by 40d in FIG. 4, light is transmitted to the projection lens 100 for a time of “4/8” by the specific control signal at bit position 2, and the bit position Light is transmitted for a time of “2/8” by a specific control signal of 1 and light is transmitted for a time of “1/8” by a specific control signal of bit position 0. As described above, in the projection display device 1 capable of performing 3-bit gradation display by time-division and synchronous control, an HDR image having a gradation number of 6 bits can be displayed.

Furthermore, the flow of the waveform information generation process according to the control program in the display control device 2 will be described based on FIG. FIG. 5 is a flowchart showing the waveform information generation process.
When the display control device 2 is turned on and the control program is started, as shown in FIG. 5, first, the process proceeds to step S100 to determine whether or not HDR image data is stored in a specific area of the RAM 2f. If it is determined (Yes), the process proceeds to step S102. If not (No), the process waits until it is stored.

When the process proceeds to step S102, the HDR image data stored in the RAM 2f is analyzed, and the process proceeds to step S104.
In step S104, it is determined whether or not the number of gradations of the HDR image is greater than or equal to a predetermined number based on the analysis result. If it is determined that the number is greater than or equal to the predetermined number (Yes), the process proceeds to step S106; ) Proceeds to step S114. For example, when the number of displayable gradations in the synchronization control is 256, the predetermined number is 257.

When the process proceeds to step S106, based on the number of gradations of the HDR image, the number of additional bits relative to the number of gradations in the synchronization control is calculated, and the process proceeds to step S108.
In step S108, based on the number of additional bits, the delay time is calculated using the above equation (1), and the process proceeds to step S110.
In step S110, based on the calculated number of additional bits and delay time, waveform information for generating a control signal necessary for gradation display is generated, and the process proceeds to step S112.

In step S112, it is determined whether or not the generation of the waveform information for all the pixels of the HDR image has been completed. If it is determined that the generation has ended (Yes), the process proceeds to step S100, and if not (No), step S106 is performed. Migrate to
On the other hand, in step S104, when the number of gradations of the HDR image is smaller than the predetermined number of gradations and the process proceeds to step S114, waveform information for generating a control signal having a pulse width corresponding to each bit of the number of gradations is obtained. The process proceeds to step S116.

In step S116, it is determined whether or not the generation of the waveform information for all the pixels of the HDR image is completed. If it is determined that the generation is completed (Yes), the process proceeds to step S100, and if not (No), the process proceeds to step S114. Migrate to
As described above, the projection display apparatus 1 displays gradation of the HDR image by the time division and synchronous drive control of the first DMD 50 and the second DMD 70 by the mirror device drive circuits 2b and 2c under the control of the display control apparatus 2. Is possible.

  Further, a specific control signal is added to the control signal at the time of synchronous control, and the supply of the specific control signal to the mirror device drive circuit 2c is delayed by a predetermined time with respect to the supply timing of the specific control signal to the mirror device drive circuit 2b. As a result, the number of gradations that can be displayed can be increased. Accordingly, it is possible to display an HDR image having the number of gradations greater than or equal to the maximum number of gradations that can be displayed by the synchronous drive control of the first DMD 50 and the second DMD 70.

[Modification 1]
In the above embodiment, the gradation display processing of the HDR image is performed by control by software. In the first modification, the display control device 3 that realizes the gradation display processing by hardware will be described based on FIG. To do. The display control device 3 is applied in place of the display control device 2 in the projection display device 1 shown in FIG.

Here, FIG. 6 is a block diagram showing a hardware configuration of the display control device 3.
As shown in FIG. 6, the display control device 3 includes an interface circuit 3a that acquires information from the outside and transmits various data to each component, and a gradation display process for HDR image data acquired from the outside. The image processing circuit 3b for performing the correction processing necessary for performing image processing, the PWM generator 3c for generating a control signal having a pulse width necessary for gradation display of the HDR image, and the signal delay processing in the signal delay unit 3e are controlled. A control unit 3d, a signal delay unit 3e that delays a control signal from the PWM generator 3c according to the control of the control unit 3d, a timing control unit 3f that controls various timings of signals supplied to the respective components, A mirror device drive circuit 3h for driving the micromirror of the first DMD 50 according to the control signal, and a micromirror of the second DMD 70 according to the control signal. Has become a mirror device drive circuit 3g for driving the over, a structure containing.

Hereinafter, a specific operation of the display control device 3 will be described.
The HDR image data input from the outside is transmitted to the image processing circuit 3b via the interface circuit 3a. In the image processing circuit 3b, control values for each pixel are extracted from the HDR image data, and the extracted control values are corrected by normalization or the like and converted into data corresponding to the gradation display processing to generate control data. The generated control data is transmitted to the PWM generator 3c. The PWM generator 3c generates a control signal having a pulse width necessary for gradation display of the input HDR image based on the control data from the image processing circuit 3b. Here, when HDR image data having a predetermined number of gradations (for example, 255) or less is input, the PWM generator 3c, like the display control apparatus 2, has a pulse width corresponding to each bit of the number of gradations. And the generated control signals are input to the control unit 3d, the delay control unit 3e, and the mirror device drive circuit 3h, respectively. In this case, the control unit 3d determines that the delay is not necessary, and controls the delay control unit 3e to pass the control signal from the PWM generator 3c and transmit it to the mirror device drive circuit 3g. The mirror device drive circuits 3g and 3h drive the first DMD 50 and the second DMD 70 at a timing synchronized with the acquisition of the control signal from the PWM generator 3c to control the reflection direction of each micromirror. In this way, gradation display of the HDR image is performed by controlling the reflection direction of the micromirrors of the first DMD 50 and the second DMD 70 in a time-sharing manner and controlling the cumulative transmission time of light to the projection lens 100. I do.

  On the other hand, when HDR image data having a number of gradations greater than the predetermined number of gradations is input, the image processing circuit 3b obtains the number of additional bits that exceeds the predetermined number of gradations. Further, in the image processing circuit 3b, the PWM generator 3c generates a control signal having a minimum pulse width (hereinafter referred to as a specific control signal) for the lower bits corresponding to the number of additional bits in the bit string of the gradation number data. For other bits, control data is generated so as to generate a control signal having a pulse width corresponding to each bit. The control data is input to the PWM generator 3c, where a control signal corresponding to the control data is generated and input to the control unit 3d, the delay control unit 3e, and the mirror device drive circuit 3h. Here, the PWM generator 3c also transmits information on the bit position to the controller 3d.

  In this case, the control unit 3d determines that it is necessary to delay the specific control signal, and controls the signal delay unit 3e to delay each specific control signal by a delay time corresponding to the number of additional bits. Here, the delay time corresponding to some number of additional bits is obtained in advance by the above equation (1), and is given to the control unit 3d. The control signal from the PWM generator 3c is synchronously supplied to the signal delay unit 3e and the mirror device drive circuit 3h, and the signal delay unit 3e is configured to send a specific control signal according to an instruction from the control unit 3d. It is delayed and supplied to the mirror device drive circuit 3g, and other control signals are passed through and supplied to the mirror device drive circuit 3g.

  That is, the specific control signals for the number of additional bits are supplied to the second DMD 70 after a predetermined time delay from the timing of supplying the specific control signals to the first DMD 50. That is, by delaying the supply of the control signal to the second DMD 70, the light transmission time of the first DMD 50 and the light transmission time of the second DMD 70 partially overlap each other at the target position. Transmit light. Therefore, the transmission time of light corresponding to the additional bits can be controlled by adjusting each delay time so that the light is transmitted to the projection lens 100 only for the time corresponding to each additional bit. Can do. However, the delay time needs to be different for each additional control signal and shorter than the pulse width of each control signal. In this way, gradation display of the HDR image is performed by controlling the reflection direction of the micromirrors of the first DMD 50 and the second DMD 70 in a time-sharing manner and controlling the cumulative transmission time of light to the projection lens 100. And adding the specific control signal and delaying the supply of the specific control signal to the mirror device drive circuit 3g for each signal by a predetermined time from the timing of supplying the specific control signal to the mirror device drive circuit 3h. 2 to control the delay of the DMD 70 to increase the number of displayable gradations.

In the first modification, the first and second DMDs 50 and 70 are driven by generating a control signal directly connected to the driving contents shown in FIG. 4, but the present invention is not limited to this. The first and second DMDs 50 and 70 may be driven by a control signal different from the control signal as shown in FIG. 4 according to the driving method of the device driving circuits 3g and 3h.
For example, in the display control device 3, the mirror device drive circuits 3g and 3h are controlled by the first and second mirrors by a control signal of a method different from the control signal as shown in FIG. 4 (for example, switching of the reflection direction by a one-shot pulse). In the case of a method for driving the second DMDs 50 and 70, the first and second DMDs 50 and 70 drive the control signals according to the driving method with the target driving contents as shown in FIG. It is generated by the PWM generator 3c.

[Modification 2]
Furthermore, as a second modification, a display control device 4 that performs the gradation number enlargement process by delaying the start of the waveform generation process of the control signal for controlling the DMD will be described with reference to FIGS. The display control device 4 is applied in place of the display control device 2 in the projection display device 1 shown in FIG. 7 is a diagram illustrating an example of a method for storing control data for gradation display in a frame memory (not shown), and FIG. 8 is a diagram illustrating a hardware configuration of the display control device 4. 9 is a diagram illustrating a detailed configuration of the PWM generator 4c and an example of a generated waveform in the PWM generator 4c.

  As shown in FIG. 8, the display control device 4 includes an interface circuit 4a for acquiring information from the outside and transmitting various data to each component, and a gradation display process for the HDR image data acquired from the outside. The image processing circuit 4b for performing correction processing necessary for performing image processing, the PWM generator 4c for generating a control signal having a pulse width necessary for gradation display of the HDR image, and for controlling the delay of the control signal, and each component A timing control 4d for controlling various timings of signals supplied to the elements, a mirror device driving circuit 4e for driving the micromirror of the first DMD 50 according to the control signal, and a micro of the second DMD 70 according to the control signal. And a mirror device driving circuit 4f for driving the mirror.

  Here, when the resolutions of the first and second DMDs 50 and 70 are 4 × 4 respectively, the gradation data of the HDR image is stored in the frame memory with the contents shown in FIG. That is, FIG. 7A shows gradation data for one screen in one frame corresponding to a bit (here, bit position 2) of gradation data, and FIG. 7C shows one pixel of the HDR image. Is the gradation data necessary for gradation display, and FIG. 7B is the gradation data necessary for gradation display of one HDR image. The storage positions of these gradation data correspond to the HDR image pixels on a one-to-one basis. Further, in the display control unit 4, the driving control of the micromirrors in the first and second DMDs 50 and 70 is performed in units of one screen as shown in FIG. In the case of an HDR image having a 6-bit gradation number, the control signals described above are generated in order for each screen with respect to 6 screens corresponding to the upper 3 bits and the lower 3 bits. The mirror device drive circuits 4e and 4f simultaneously drive the micromirrors corresponding to each screen according to the control signal for each screen.

  Further, as shown in FIG. 9A, the PWM generator 4c includes a PWM generation control circuit 400 that controls the generation timing of the control signal waveforms of the PWM generation circuits 410 and 420, and a mirror that is controlled by the PWM generation control circuit 400. A configuration including a PWM generation circuit 410 that generates a control signal waveform for the device drive circuit 4e, and a PWM generation circuit 420 that generates a control signal waveform for the mirror device drive circuit 4f under the control of the PWM generation control circuit 400; It has become.

Hereinafter, a specific operation of the display control device 4 will be described.
The HDR image data input from the outside is transmitted to the image processing circuit 4b via the interface circuit 4a. In the image processing circuit 4b, control values of each pixel are extracted from the HDR image data, and the extracted control values are corrected by normalization or the like, converted into data corresponding to the gradation display process, and control data is generated. The generated control data is transmitted to the PWM generator 4c. The PWM generator 4c generates a control signal having a pulse width necessary for gradation display of the input HDR image based on the control data from the image processing circuit 4b. Here, when HDR image data having a predetermined number of gradations (for example, 255) or less is input, the PWM generation device 4c causes the PWM generation control circuit 400 to correspond to one screen corresponding to each bit of the number of gradations. Pulse width control signals are generated at the same timing in the PWM generation circuits 410 and 420, and the generated control signals are input to the mirror device drive circuits 4e and 4f in a time-sharing manner, respectively.

  The mirror device drive circuits 4e and 4f drive the first DMD 50 and the second DMD 70 at a timing synchronized with the acquisition of the control signal from the PWM generator 4c to control the reflection direction of each micromirror. In this way, gradation display of the HDR image is performed by controlling the reflection direction of the micromirrors of the first DMD 50 and the second DMD 70 in a time-sharing manner and controlling the cumulative transmission time of light to the projection lens 100. I do.

  On the other hand, when HDR image data having a number of gradations greater than the predetermined number of gradations is input, the image processing circuit 4b obtains the number of additional bits that exceeds the predetermined number of gradations. Further, in the image processing circuit 4b, the PWM generator 4c generates a control signal having a minimum pulse width (hereinafter referred to as a specific control signal) for the lower bits corresponding to the number of additional bits in the bit string of gradation data. For other bits, control data is generated so as to generate a control signal having a pulse width corresponding to each bit. This control data is input to the PWM generator 4c, where a control signal corresponding to the control data is generated and input to the mirror device drive circuits 4e and 4f, respectively. Here, the PWM generation device 4c controls the generation timing of the specific control signal in the PWM generation circuits 410 and 420 by the PWM generation control circuit 400 when the control signal is generated. This timing control is performed based on the number of specific control signals to be generated, and is delayed from the timing at which the PWM generation circuit 410 generates the specific control signal, for example, by a delay time calculated using the above equation (1). The PWM control circuit 420 generates a specific control signal at the same timing. That is, as shown in FIG. 9B, the PWM generation circuit 420 delays the generation start time of the specific control signal according to the control of the PWM generation control circuit 400. Therefore, the specific control signal delayed in the PWM generation circuit 420 is input to the mirror device drive circuit 4f. The mirror device drive circuits 4e and 4f drive the second DMD 70 with a predetermined time delay from the timing for driving the first DMD 50 in accordance with the specific control signal for the number of additional bits. That is, by delaying the driving of the second DMD 70, the light is transmitted to the target position only during the time when the light transmission time of the first DMD 50 and the light transmission time of the second DMD 70 partially overlap each other. . Therefore, the transmission time of light corresponding to the additional bits can be controlled by adjusting each delay time so that the light is transmitted to the projection lens 100 only for the time corresponding to each additional bit. Can do. However, the delay time needs to be different for each additional control signal and shorter than the pulse width of each control signal. In this way, gradation display of the HDR image is performed by controlling the reflection direction of the micromirrors of the first DMD 50 and the second DMD 70 in a time-sharing manner and controlling the cumulative transmission time of light to the projection lens 100. And adding a specific control signal and delaying the supply of the specific control signal to the mirror device drive circuit 4f for each signal by a predetermined time from the timing of supplying the specific control signal to the mirror device drive circuit 4e. 2 to control the delay of the DMD 70 to increase the number of displayable gradations.

  In the second modification, as in the first modification, the first and second DMDs 50 and 70 are driven by generating control signals directly connected to the driving contents shown in FIG. However, the present invention is not limited to this, and the first and second DMDs 50 and 70 may be driven by a control signal different from the control signal shown in FIG. 4 in accordance with the drive method of the mirror device drive circuits 4e and 4f. .

[Modification 3]
Next, a case where a reflective liquid crystal light valve is used as the light modulation element of the projection display device will be described.
FIG. 10 is a diagram showing a main optical configuration of a single-plate projection display device 6 using reflective liquid crystal light valves for the first light modulation element and the second light modulation element. In addition, about the component same as the component shown in FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.
As shown in FIG. 10, the projection display device 6 includes a light source 10, a color filter 30, a first reflective liquid crystal light valve 210, a second reflective liquid crystal light valve 220, a first polarizing beam splitter 230, and a second polarized beam. It includes a splitter 240, a projection lens 100, etc., and these are optically arranged in series.
Both the first reflective liquid crystal light valve 210 and the second reflective liquid crystal light valve 220 are digital drive type liquid crystal light valves. The first polarizing beam splitter 230 and the second polarizing beam splitter 240 are optical elements that separate the light bundle into two by a birefringent crystal, and transmit P-polarized light but reflect S-polarized light.
The white light emitted from the light source 10 becomes P-polarized light by passing through the polarization conversion element 15, passes through the condenser lens 20, the color filter 30, and the condenser lens 40, and enters the first polarizing beam splitter 230. It is injected towards.
The light that has entered the first polarizing beam splitter 230 is P-polarized light, and therefore passes through the first polarizing beam splitter 230 (goes straight) and enters the first reflective liquid crystal light valve 210 through the λ / 4 plate 250. The light that has entered the first reflective liquid crystal light valve 210 is modulated and reflected, and then enters the first polarizing beam splitter 230 through the λ / 4 plate 250 again.
The light that has entered the first polarizing beam splitter 230 again is S-polarized light, and is reflected by the first polarizing beam splitter 230 and then enters the relay lens 270. The relay lens 270 has telecentricity, and an image modulated on the first reflective liquid crystal light valve 210 is accurately formed on the emission side. Then, the light from the relay lens 270 passes through the condenser lens 60 and is emitted toward the second polarizing beam splitter 240.
Since the light incident on the second polarizing beam splitter 240 is S-polarized light, it is reflected by the second polarizing beam splitter 240 and then enters the second reflective liquid crystal light valve 220 via the λ / 4 plate 260. The light incident on the second reflective liquid crystal light valve 220 is modulated and reflected, and then enters the second polarizing beam splitter 240 again through the λ / 4 plate 260. Since the incident light is P-polarized light, it passes through the second polarization beam splitter 240 (goes straight).
The P-polarized light modulated by the two reflective liquid crystal light valves 210 and 220 is projected onto the screen 110 through the projection lens 100.
As described above, since the two reflective liquid crystal light valves 210 and 220 are digitally driven, the brightness is usually lowered and the contrast is not changed. Therefore, by shifting the timing of the PWM control signal that drives the two reflective liquid crystal light valves 210 and 220, the number of gradations can be increased and the contrast can be greatly increased. Since each color is modulated by two modulation elements, the calculation of each pixel is simplified.

[Modification 4]
FIG. 11 is a diagram showing a main optical configuration of a single-plate projection display device 7 using a DMD as the first light modulation element and a reflective liquid crystal light valve as the second light modulation element. In addition, about the component same as the component shown in FIG.1 and FIG.10, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIG. 11, the projection display device 7 includes a light source 10, a color filter 30, a DMD 50, a reflective liquid crystal light valve 220, a polarizing beam splitter 240, a projection lens 100, and the like, which are optically connected in series. The arrangement is arranged.
The white light emitted from the light source 10 passes through the polarization conversion element 15 to become P-polarized light, and is emitted toward the condenser lens 20, the color filter 30, and the DMD 50. The P-polarized light modulated in the DMD enters the relay lens 270 and is emitted toward the polarization beam splitter 240.
Since the light incident on the polarization beam splitter 240 is P-polarized light, the light passes through the polarization beam splitter 240 (goes straight), and enters the reflective liquid crystal light valve 220 via the λ / 4 plate 260. Then, the light incident on the reflective liquid crystal light valve 220 is reflected after being modulated, and again enters the polarization beam splitter 240 via the λ / 4 plate 260. Since the incident light is S-polarized light, it is reflected by the polarization beam splitter 240 and emitted.
The S-polarized light modulated by the DMD 50 and the reflective liquid crystal light valve 220 is projected onto the screen 110 via the projection lens 100.

[Modification 5]
FIG. 12 is a diagram showing a main optical configuration of a three-plate projection display device 8 using reflective liquid crystal light valves for the first light modulation element and the second light modulation element. In addition, about the component same as the component shown in FIG.1, FIG.10 and FIG.11, the same code | symbol is attached | subjected and description is abbreviate | omitted.
As shown in FIG. 12, the projection display device 8 includes a light source 10, a first reflective liquid crystal light valve 210, second reflective liquid crystal light valves 220r, 220g, and 220b, a first polarizing beam splitter 230, and a second polarized beam. It includes a splitter 240r, 240g, 240b, a first dichroic mirror 310, a second dichroic mirror 320, a color synthesis prism 330, a projection lens 100, and the like. Since the color filter 30 is not used, the light use efficiency can be increased.
The first dichroic mirror 310 and the second dichroic mirror 320 separate light in two or more wavelength ranges by dielectric multilayer films having different refractive indexes. The color synthesis prism 330 synthesizes red, green, and blue light.
The white light emitted from the light source 10 becomes P-polarized light by passing through the polarization conversion element 15, passes through the condenser lens 20 and the condenser lens 40, and is emitted toward the first polarization beam splitter 230. The
The light that has entered the first polarizing beam splitter 230 is P-polarized light, and therefore passes through the first polarizing beam splitter 230 (goes straight) and enters the first reflective liquid crystal light valve 210 through the λ / 4 plate 250. The light that has entered the first reflective liquid crystal light valve 210 is modulated and reflected, and then enters the first polarizing beam splitter 230 through the λ / 4 plate 250 again.
The light that has entered the first polarization beam splitter 230 again is S-polarized light, and therefore is reflected by the first polarization beam splitter 230, enters the relay lens 270, and is emitted toward the first dichroic mirror 310. .
The light incident on the first dichroic mirror 310 is separated and reflected into blue and other (red and green) light.
The blue light is reflected by the mirror 340, passes through the condenser lens 60, and enters the second polarizing beam splitter 240b. Then, since it is S-polarized light, it is reflected by the second polarizing beam splitter 240b and enters the second reflective liquid crystal light valve 220b via the λ / 4 plate 260. Then, the blue light incident on the second reflective liquid crystal light valve 220b is modulated and reflected, and again enters the second polarizing beam splitter 240b via the λ / 4 plate 260. Since the incident blue light is P-polarized light, it is transmitted through the second polarization beam splitter 240b and emitted.
On the other hand, the red and green lights are reflected by the mirror 340, then enter the second dichroic mirror 320, are separated into red light and green light, are reflected, pass through the condenser lens 60, and are respectively second polarized light. The light enters the beam splitters 240r and 240g. Then, similarly to the blue light, the light is modulated by the second reflective liquid crystal light valves 220r and 220g, becomes P-polarized light, passes through the second polarizing beam splitters 240r and 240g, and is emitted.
The P-polarized light modulated by the first reflective liquid crystal light valve 210 and the second reflective liquid crystal light valve 220r, 220g, 220b is incident on the color synthesis prism 330 and synthesized, and then the projection lens 100. And then projected onto the screen 110.

[Modification 6]
FIG. 13 is a diagram showing a main optical configuration of a three-plate projection display device 9 using a DMD as the first light modulation element and a reflective liquid crystal light valve as the second light modulation element. In addition, about the component same as the component shown in FIGS. 1, 10-10, the same code | symbol is attached | subjected and description is abbreviate | omitted.
As shown in FIG. 13, the projection display device 9 includes a light source 10, a DMD 50, reflective liquid crystal light valves 220r, 220g, and 220b, polarizing beam splitters 240r, 240g, and 240b, a first dichroic mirror 310, and a second dichroic. The mirror 320, the color synthesis prism 330, the projection lens 100, and the like are included. Since the color filter 30 is not used, the light use efficiency can be increased.
The white light emitted from the light source 10 becomes P-polarized light by passing through the polarization conversion element 15, passes through the condenser lens 20 and the λ / 2 plate 350, becomes S-polarized light, and is emitted toward the DMD 50. The The S-polarized light modulated by the DMD 50 enters the relay lens 270 and is emitted toward the first dichroic mirror 310.
The light incident on the first dichroic mirror 310 is separated and reflected into blue and other (red and green) light.
The blue light is reflected by the mirror 340, passes through the condenser lens 60, and enters the second polarizing beam splitter 240b. Then, since it is S-polarized light, it is reflected by the second polarizing beam splitter 240b and enters the second reflective liquid crystal light valve 220b via the λ / 4 plate 260. Then, the blue light incident on the second reflective liquid crystal light valve 220b is modulated and reflected, and again enters the second polarizing beam splitter 240b via the λ / 4 plate 260. Since the incident blue light is P-polarized light, it is transmitted through the second polarization beam splitter 240b and emitted.
On the other hand, the red and green lights are reflected by the mirror 340, then enter the second dichroic mirror 320, are separated into red light and green light, are reflected, pass through the condenser lens 60, and are respectively second polarized light. The light enters the beam splitters 240r and 240g. Then, similarly to the blue light, the light is modulated by the second reflection type liquid crystal light valves 220r and 220g and becomes P-polarized light and is emitted from the second polarization beam splitters 240r and 240g.
The P-polarized light modulated by the DMD 50 and the reflective liquid crystal light valves 220r, 220g, and 220b is incident on the color synthesis prism 330, synthesized, and then projected onto the screen 110 via the projection lens 100.

In the above embodiment, the first DMD 50 (first reflective liquid crystal light valve 210) and the second DMD 70 (second reflective liquid crystal light valve 220) are the inventions 1, 2, 6, 7, 9, 11-11. 14, 18, 19, 23, 24, 28, 29, 33, and 34.
In the above embodiment, the waveform information generated by the control program, the generation of the control signal by the mirror device drive circuits 2b and 3b corresponding to the waveform information, and the first DMD 50 (first reflective liquid crystal light valve 210) And the second DMD 70 (second reflective liquid crystal light valve 220) synchronous drive control processing corresponds to the control signal supply means of any one of the inventions 2, 3, 6, 7, 14, 15 and 18. .

In the above embodiment, the waveform information generated by the control program and the specific control signal are delayed and supplied to the second DMD 70 (second reflective liquid crystal light valve 220) by the mirror device 2c according to the waveform information. The drive control process corresponds to the signal delay means of any one of the inventions 1-3, 7, 10, 13-15, 19 and 22.
In the above embodiment, the first DMD 50 (first reflective liquid crystal light valve 210) and the second DMD 70 (second reflective liquid crystal light valve 220) are used by the PWM generator 3c and the mirror device drive circuits 3g and 3h. The processing for synchronously driving the control corresponds to the control signal supply means of any one of the inventions 2, 3, 6, 7, 14, 15, and 18.

In the above-described embodiment, the PWM generator 3c, the control unit 3d, the signal delay unit 3e, and the mirror device drive circuits 3g and 3h send the specific control signal to the second DMD 70 (second reflective liquid crystal light valve 220). The process of delay supply and drive control corresponds to the signal delay means of any one of inventions 1-3, 7, 10, 13-15, 19 and 22.
In the above embodiment, the first DMD 50 (first reflective liquid crystal light valve 210) and the second DMD 70 (second reflective liquid crystal light valve 220) are used by the PWM generator 4c and the mirror device drive circuits 4e and 4f. The process for controlling the synchronous drive corresponds to the control signal supply means of any one of the inventions 2, 4, 6, 7, 14, 16 and 18.

In the above embodiment, the PWM generator 4c and the mirror device drive circuits 4e and 4f perform the process of delaying and supplying the specific control signal to the second DMD 70 (second reflective liquid crystal light valve 220). , 1, 2, 4, 7, 10, 13, 14, 16, 19 and 22.
In the above embodiment, the DMD or the reflective liquid crystal light valve is used as the light modulation element. However, the present invention is not limited to this, and a light modulation element such as a transmission liquid crystal light valve can also be used.

In the above embodiment, whether or not the input HDR image has a predetermined number of gradations or more is determined by a program or hardware. However, the present invention is not limited to this. A configuration may be adopted in which the processing is fixedly performed in accordance with the logarithm and the determination unit is not provided.
Further, in the above embodiment, the case where the control program stored in advance in the ROM 2e is executed when executing the processing shown in the flowchart of FIG. 5 is described, but the procedure is not limited to this. The program may be read from the storage medium storing the program into the RAM 2f and executed.

  The storage medium includes a semiconductor storage medium such as RAM and ROM, a magnetic storage type storage medium such as FD and HD, an optical reading type storage medium such as CD, CDV, LD, and DVD, and a magnetic storage type such as MO. The optical reading type storage medium includes any storage medium as long as it is a computer-readable storage medium regardless of electronic, magnetic, optical, or other reading methods.

It is a figure which shows the main optical structures of the projection type display apparatus 1 which concerns on this invention. 3 is a block diagram showing a hardware configuration of a display control device 2. FIG. It is a figure which shows the basic waveform used for display control. It is a figure which shows an example of the drive control waveform for the gradation number expansion of a HDR image. It is a flowchart which shows a waveform information generation process. 3 is a block diagram showing a hardware configuration of a display control device 3. FIG. It is a figure which shows an example of the storage method to the frame memory of the control data for gradation display. 2 is a diagram illustrating a hardware configuration of a display control device 4. FIG. It is a figure which shows an example of the detailed structure of the PWM generator 4c, and the generated waveform of the PWM generator 4c. It is a figure which shows the main optical structures of the projection type display apparatus 6 which concerns on this invention. It is a figure which shows the main optical structures of the projection type display apparatus 7 which concerns on this invention. It is a figure which shows the main optical structure of the projection type display apparatus 8 which concerns on this invention. It is a figure which shows the main optical structure of the projection type display apparatus 9 which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,6,7,8,9 ... Projection type display device, 2,3,4: Display control device, 2a, 3a, 4a ... Interface circuit, 2b, 2c, 3g, 3h, 4e, 4f ... Mirror device drive circuit 2d ... CPU, 2e ... ROM, 2f ... RAM, 3b, 4b ... image processing circuit, 3c, 4c ... PWM generator, 3d ... control unit, 3e ... signal delay unit, 3f, 4d ... timing control unit, 10 ... Light source, 30 ... color filter, 40, 60 ... condensing lens, 50 ... first DMD, 70 ... second DMD, 100 ... projection lens, 110 ... screen, 210 ... first reflective liquid crystal light valve, 220 ... Second reflection type liquid crystal light valve, 400 ... PWM generation control circuit, 410, 420 ... PWM generation circuit

Claims (10)

Two or more optical transmission elements having a plurality of optical transmission units capable of independently controlling the transmission state and non-transmission state of incident light in a predetermined direction are optically arranged in series, and the two or more optical transmission elements are provided. An apparatus for controlling the transmission state and non-transmission state of light from a light source via a light transmission element and displaying an image,
In order to control the transmission state and the non-transmission state of the light transmission element, a plurality of control signals having specific pulse widths corresponding to specific bits in a bit string indicating the number of gradations based on the number of gradations of the display image are generated. Control signal supply means capable of supplying the generated control signal in a time-sharing manner and at a timing synchronized with each of the two or more light transmission elements;
A delay time for the control signal having the specific pulse width is calculated based on the specific bit, and the control signal having the specific pulse width is supplied to any one of the two or more optical transmission elements based on the calculated delay time. An optical display device comprising: a signal delay unit capable of delaying a timing for supplying the control signal having the specific pulse width to another optical transmission element by a predetermined time before the timing to perform. The specific pulse width, an optical display device according to claim 1, wherein the the same as the pulse width of the control signal corresponding to the least significant bits except for the specific bit of the bit string indicating the number of gradations. 3. The optical display device according to claim 1, wherein the supply interval of the control signal having the specific pulse width is larger than the specific pulse width. When the number of the specific bits is n (n is an integer) and the bit position of the specific bit in the bit string indicating the number of gradations of the display image is m (m is an integer of 0 to (n−1)), The signal delay means calculates a time obtained by multiplying a coefficient obtained by (2n-2m) / 2n by the time of the specific pulse width as a delay time of the control signal of the specific pulse width. optical display device according to any one of claims 1 to 3, characterized in that. It said signal delay means, any one of claims 1 to 4, characterized in that it is any one so as to delay a predetermined time among the plurality of control signals on the basis of the number of gradations optical display device according to. 6. The signal delay unit according to claim 1, wherein the signal delay means delays a generation timing of any one of the plurality of control signals based on the number of gradations for a predetermined time . 2. An optical display device according to item 1 . The two or more the number of the light transmission portion in the optical transmission device, the optical display device according to any one of claims 1 to 6, characterized in that the equally between the light transmission device. The optical display device according to any one of claims 1 to 7 , wherein the two or more light transmission elements are reflection type light transmission elements. Two or more optical transmission elements having a plurality of optical transmission units capable of independently controlling the transmission state and non-transmission state of incident light in a predetermined direction are optically arranged in series, and the two or more optical transmission elements are provided. A program for controlling an optical display device that displays an image by controlling the transmission state and non-transmission state of light from a light source via a light transmission element,
In order to control the transmission state and the non-transmission state of the light transmission element, a plurality of control signals having specific pulse widths corresponding to specific bits in a bit string indicating the number of gradations based on the number of gradations of the display image are generated. Control signal supply means capable of supplying the generated control signal in a time-sharing manner and at a timing synchronized with each of the two or more optical transmission elements; and
A delay time for the control signal having the specific pulse width is calculated based on the specific bit, and the control signal having the specific pulse width is supplied to any one of the two or more optical transmission elements based on the calculated delay time. A program for causing a computer to execute processing realized as signal delay means capable of delaying a timing for supplying the control signal having the specific pulse width to another optical transmission element by a predetermined time before timing An optical display device control program. Two or more optical transmission elements having a plurality of optical transmission units capable of independently controlling the transmission state and non-transmission state of incident light in a predetermined direction are optically arranged in series, and the two or more optical transmission elements are provided. A method of controlling an optical display device that displays an image by controlling the transmission state and non-transmission state of light from a light source via a light transmission element,
In order to control the transmission state and the non-transmission state of the light transmission element, a plurality of control signals having specific pulse widths corresponding to specific bits in a bit string indicating the number of gradations based on the number of gradations of the display image are generated. A control signal supply step of supplying the generated control signal in a time-sharing manner and at a timing synchronized with each of the two or more light transmission elements;
A delay time for the control signal having the specific pulse width is calculated based on the specific bit, and the control signal having the specific pulse width is supplied to any one of the two or more optical transmission elements based on the calculated delay time. And a signal delay step capable of delaying a timing for supplying the control signal having the specific pulse width to another optical transmission element by a predetermined time before the timing to perform the optical display device control method.

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